SmogRank / South Korea / Gangwon-do

Air quality in Hongch’ŏn

No new readings from Hongch’ŏn's monitors since 1 Oct. Some networks publish days late. The figures below are from before then; they update when the data returns.

Gangwon-do, South Korea. PM2.5 from 1 reference monitor. None of them reported in the last 24 hours.

27US AQI
Good

Mean for 1 Oct, the most recent day with readings, 0.3× the WHO 24-hour guideline. PM2.5 4.8 µg/m³.

Rank, worst first

24 hours–not enough data
7 days#1,143of 2,594, at 46 US AQI (8.3 µg/m³), 7 days to 1 Oct
30 days#189of 2,622, at 103 US AQI (36.4 µg/m³), 28 days to 1 Oct
This year#139of 2,447, at 130 US AQI (47.4 µg/m³), to 1 Oct

Why it ranks here

Seasonal. Over the past year its worst months were May, June, November, averaging up to 100.6 µg/m³ against 5.0 in its cleanest month. Seasonal peaks usually come from heating, crop burning, fire or dust seasons.

Based on Hongch’ŏn's own measurements; causes are the usual kinds for a pattern like this, not a confirmed source.

Bad-air episodes that reached Hongch’ŏn

Times when Hongch’ŏn and many cities around it had PM2.5 at twice their usual or more on the same days. All episodes.

The last 12 months, day by day

1102031Nov 2025DecJan 2026FebMarAprMayJunJulAugSepOct2025-11-01: 9.3 µg/m³2025-11-02: 6.5 µg/m³2025-11-03: 9.1 µg/m³2025-11-04: 10.6 µg/m³2025-11-05: 16.5 µg/m³2025-11-06: 19.2 µg/m³2025-11-07: 20.6 µg/m³2025-11-08: 11.5 µg/m³2025-11-09: 13.9 µg/m³2025-11-10: 6.9 µg/m³2025-11-11: 11.3 µg/m³2025-11-12: 15.2 µg/m³2025-11-13: 21.6 µg/m³2025-11-14: 19.7 µg/m³2025-11-15: 14.1 µg/m³2025-11-16: 18.1 µg/m³2025-11-17: 10.4 µg/m³2025-11-18: 7.8 µg/m³2025-11-19: 13.5 µg/m³2025-11-20: 436.0 µg/m³2025-11-21: 7.2 µg/m³2025-11-22: 18.2 µg/m³2025-11-23: 32.3 µg/m³2025-11-24: 46.1 µg/m³2025-11-25: 38.6 µg/m³2025-11-26: 864.0 µg/m³2025-11-27: 852.0 µg/m³2025-11-28: 425.0 µg/m³2025-11-29: 10.4 µg/m³2025-11-30: 32.6 µg/m³2025-12-01: 443.0 µg/m³2025-12-02: 11.0 µg/m³2025-12-03: 4.3 µg/m³2025-12-04: 5.9 µg/m³2025-12-05: 16.0 µg/m³2025-12-06: 16.0 µg/m³2025-12-07: 37.4 µg/m³2025-12-08: 18.1 µg/m³2025-12-09: 10.2 µg/m³2025-12-10: 20.5 µg/m³2025-12-11: 23.2 µg/m³2025-12-12: 427.0 µg/m³2025-12-13: 9.3 µg/m³2025-12-14: 9.7 µg/m³2025-12-15: 16.3 µg/m³2025-12-16: 23.7 µg/m³2025-12-17: 31.0 µg/m³2025-12-18: 35.4 µg/m³2025-12-19: 27.9 µg/m³2025-12-20: 38.0 µg/m³2025-12-21: 5.5 µg/m³2025-12-22: 10.6 µg/m³2025-12-23: 14.3 µg/m³2025-12-24: 17.0 µg/m³2025-12-25: 8.0 µg/m³2025-12-26: 7.5 µg/m³2025-12-27: 13.6 µg/m³2025-12-28: 29.4 µg/m³2025-12-29: 42.0 µg/m³2025-12-30: 24.6 µg/m³2025-12-31: 7.0 µg/m³2026-01-01: 7.0 µg/m³2026-01-02: 11.6 µg/m³2026-01-03: 21.5 µg/m³2026-01-04: 29.5 µg/m³2026-01-05: 23.5 µg/m³2026-01-06: 21.4 µg/m³2026-01-07: 24.0 µg/m³2026-01-08: 9.9 µg/m³2026-01-09: 17.3 µg/m³2026-01-10: 22.7 µg/m³2026-01-11: 6.7 µg/m³2026-01-12: 11.6 µg/m³2026-01-13: 11.5 µg/m³2026-01-14: 11.2 µg/m³2026-01-15: 31.9 µg/m³2026-01-16: 51.7 µg/m³2026-01-17: 37.5 µg/m³2026-01-18: 33.7 µg/m³2026-01-19: 22.4 µg/m³2026-01-20: 8.2 µg/m³2026-01-21: 12.6 µg/m³2026-01-22: 7.2 µg/m³2026-01-23: 18.7 µg/m³2026-01-24: 16.0 µg/m³2026-01-25: 9.0 µg/m³2026-01-26: 15.9 µg/m³2026-01-27: 24.5 µg/m³2026-01-28: 14.9 µg/m³2026-01-29: 13.7 µg/m³2026-01-30: 14.6 µg/m³2026-01-31: 22.0 µg/m³2026-02-01: 21.8 µg/m³2026-02-02: 25.0 µg/m³2026-02-03: 22.3 µg/m³2026-02-04: 44.1 µg/m³2026-02-05: 61.5 µg/m³2026-02-06: 18.3 µg/m³2026-02-07: 8.9 µg/m³2026-02-08: 11.3 µg/m³2026-02-09: 14.6 µg/m³2026-02-10: 26.8 µg/m³2026-02-11: 43.6 µg/m³2026-02-12: 52.2 µg/m³2026-02-13: 68.0 µg/m³2026-02-14: 79.4 µg/m³2026-02-15: 41.8 µg/m³2026-02-16: 15.2 µg/m³2026-02-17: 12.6 µg/m³2026-02-18: 20.0 µg/m³2026-02-19: 19.7 µg/m³2026-02-20: 34.4 µg/m³2026-02-21: 45.0 µg/m³2026-02-22: 30.8 µg/m³2026-02-23: 7.5 µg/m³2026-02-24: 9.0 µg/m³2026-02-25: 10.9 µg/m³2026-02-26: 8.1 µg/m³2026-02-27: 3.5 µg/m³2026-02-28: 9.0 µg/m³2026-03-01: 8.8 µg/m³2026-03-02: 1.3 µg/m³2026-03-03: 1.3 µg/m³2026-03-04: 5.9 µg/m³2026-03-05: 19.5 µg/m³2026-03-06: 19.0 µg/m³2026-03-07: 18.1 µg/m³2026-03-08: 16.4 µg/m³2026-03-09: 31.7 µg/m³2026-03-10: 42.7 µg/m³2026-03-11: 29.0 µg/m³2026-03-12: 19.2 µg/m³2026-03-13: 12.0 µg/m³2026-03-14: 13.4 µg/m³2026-03-15: 31.0 µg/m³2026-03-16: 34.5 µg/m³2026-03-17: 31.0 µg/m³2026-03-18: 29.8 µg/m³2026-03-19: 17.2 µg/m³2026-03-20: 18.9 µg/m³2026-03-21: 28.1 µg/m³2026-03-22: 25.8 µg/m³2026-03-23: 25.2 µg/m³2026-03-24: 30.9 µg/m³2026-03-25: 22.0 µg/m³2026-03-26: 30.7 µg/m³2026-03-27: 52.5 µg/m³2026-03-28: 45.2 µg/m³2026-03-29: 28.0 µg/m³2026-03-30: 27.0 µg/m³2026-03-31: 11.2 µg/m³2026-04-01: 12.0 µg/m³2026-04-02: 21.1 µg/m³2026-04-03: 22.7 µg/m³2026-04-04: 20.6 µg/m³2026-04-05: 17.8 µg/m³2026-04-06: 11.1 µg/m³2026-04-07: 4.0 µg/m³2026-04-08: 11.7 µg/m³2026-04-09: 16.0 µg/m³2026-04-10: 8.7 µg/m³2026-04-11: 16.9 µg/m³2026-04-12: 10.7 µg/m³2026-04-13: 9.8 µg/m³2026-04-14: 12.0 µg/m³2026-04-15: 11.4 µg/m³2026-04-16: 6.3 µg/m³2026-04-17: 11.6 µg/m³2026-04-18: 15.2 µg/m³2026-04-19: 13.8 µg/m³2026-04-20: 17.1 µg/m³2026-04-21: 16.5 µg/m³2026-04-22: 14.3 µg/m³2026-04-23: 10.8 µg/m³2026-04-24: 4.3 µg/m³2026-04-25: 9.1 µg/m³2026-04-26: 8.0 µg/m³2026-04-27: 10.0 µg/m³2026-04-28: 11.3 µg/m³2026-04-29: 5.3 µg/m³2026-04-30: 7.2 µg/m³2026-05-01: 9.5 µg/m³2026-05-02: 28.5 µg/m³2026-05-03: 11.9 µg/m³2026-05-04: 6.7 µg/m³2026-05-05: 8.1 µg/m³2026-05-06: 844.0 µg/m³2026-05-07: 14.5 µg/m³2026-05-08: 7.0 µg/m³2026-05-09: 7.0 µg/m³2026-05-10: 8.3 µg/m³2026-05-11: 10.8 µg/m³2026-05-12: 10.6 µg/m³2026-05-13: 12.8 µg/m³2026-05-14: 12.1 µg/m³2026-05-15: 10.6 µg/m³2026-05-16: 16.0 µg/m³2026-05-17: 14.9 µg/m³2026-05-18: 15.9 µg/m³2026-05-19: 18.6 µg/m³2026-05-20: 14.7 µg/m³2026-05-21: 1,310.0 µg/m³2026-05-22: 9.8 µg/m³2026-05-23: 9.9 µg/m³2026-05-24: 10.8 µg/m³2026-05-25: 13.1 µg/m³2026-05-26: 16.8 µg/m³2026-05-27: 13.3 µg/m³2026-05-28: 6.0 µg/m³2026-05-29: 11.9 µg/m³2026-05-30: 12.1 µg/m³2026-05-31: 13.0 µg/m³2026-06-01: 14.8 µg/m³2026-06-02: 23.7 µg/m³2026-06-03: 23.5 µg/m³2026-06-04: 18.2 µg/m³2026-06-05: 9.3 µg/m³2026-06-06: 8.1 µg/m³2026-06-07: 7.8 µg/m³2026-06-08: 9.9 µg/m³2026-06-09: 6.8 µg/m³2026-06-10: 846.0 µg/m³2026-06-11: 18.2 µg/m³2026-06-12: 430.0 µg/m³2026-06-13: 12.0 µg/m³2026-06-14: 11.4 µg/m³2026-06-15: 9.1 µg/m³2026-06-16: 432.0 µg/m³2026-06-17: 14.6 µg/m³2026-06-18: 23.0 µg/m³2026-06-19: 15.6 µg/m³2026-06-20: 7.2 µg/m³2026-06-21: 4.8 µg/m³2026-06-22: 8.0 µg/m³2026-06-23: 3.8 µg/m³2026-06-24: 5.8 µg/m³2026-06-25: 4.4 µg/m³2026-06-26: 836.0 µg/m³2026-06-27: 7.8 µg/m³2026-06-28: 10.3 µg/m³2026-06-29: 13.3 µg/m³2026-06-30: 14.6 µg/m³2026-07-01: 11.2 µg/m³2026-07-02: 12.5 µg/m³2026-07-03: 13.8 µg/m³2026-07-04: 19.9 µg/m³2026-07-05: 15.8 µg/m³2026-07-06: 8.8 µg/m³2026-07-07: 7.7 µg/m³2026-07-08: 426.0 µg/m³2026-07-09: 4.3 µg/m³2026-07-10: 6.7 µg/m³2026-07-11: 10.4 µg/m³2026-07-12: 14.6 µg/m³2026-07-13: 13.3 µg/m³2026-07-14: 6.9 µg/m³2026-07-15: 8.8 µg/m³2026-07-16: 21.7 µg/m³2026-07-17: 23.3 µg/m³2026-07-18: 4.8 µg/m³2026-07-19: 5.7 µg/m³2026-07-20: 7.8 µg/m³2026-07-21: 5.6 µg/m³2026-07-22: 6.6 µg/m³2026-07-23: 9.2 µg/m³2026-07-24: 845.0 µg/m³2026-07-25: 10.4 µg/m³2026-07-26: 7.8 µg/m³2026-07-27: 8.1 µg/m³2026-07-28: 13.8 µg/m³2026-07-29: 13.8 µg/m³2026-07-30: 10.1 µg/m³2026-07-31: 430.0 µg/m³2026-08-01: 19.2 µg/m³2026-08-02: 16.1 µg/m³2026-08-03: 12.7 µg/m³2026-08-04: 9.8 µg/m³2026-08-05: 840.0 µg/m³2026-08-06: 8.5 µg/m³2026-08-07: 8.8 µg/m³2026-08-08: 6.0 µg/m³2026-08-09: 5.6 µg/m³2026-08-10: 421.0 µg/m³2026-08-11: 5.5 µg/m³2026-08-12: 4.6 µg/m³2026-08-13: 3.7 µg/m³2026-08-14: 4.5 µg/m³2026-08-15: 424.0 µg/m³2026-08-16: 12.1 µg/m³2026-08-17: 7.8 µg/m³2026-08-18: 10.5 µg/m³2026-08-19: 18.7 µg/m³2026-08-20: 24.4 µg/m³2026-08-21: 14.7 µg/m³2026-08-22: no data2026-08-23: 5.0 µg/m³2026-08-24: 15.2 µg/m³2026-08-25: no data2026-08-26: no data2026-08-27: 7.5 µg/m³2026-08-28: 8.1 µg/m³2026-08-29: 8.3 µg/m³2026-08-30: 6.4 µg/m³2026-08-31: 2.7 µg/m³2026-09-01: 2.0 µg/m³2026-09-02: no data2026-09-03: no data2026-09-04: 4.3 µg/m³2026-09-05: 3.9 µg/m³2026-09-06: 3.3 µg/m³2026-09-07: 4.0 µg/m³2026-09-08: 4.8 µg/m³2026-09-09: 3.0 µg/m³2026-09-10: 2.0 µg/m³2026-09-11: 836.0 µg/m³2026-09-12: 5.8 µg/m³2026-09-13: 7.6 µg/m³2026-09-14: 13.0 µg/m³2026-09-15: 10.8 µg/m³2026-09-16: 6.8 µg/m³2026-09-17: 4.7 µg/m³2026-09-18: 3.6 µg/m³2026-09-19: 4.8 µg/m³2026-09-20: 6.3 µg/m³2026-09-21: 6.2 µg/m³2026-09-22: 7.1 µg/m³2026-09-23: 8.7 µg/m³2026-09-24: 14.5 µg/m³2026-09-25: 8.6 µg/m³2026-09-26: 5.8 µg/m³2026-09-27: 6.5 µg/m³2026-09-28: 8.4 µg/m³2026-09-29: 9.9 µg/m³2026-09-30: 13.8 µg/m³2026-10-01: 4.8 µg/m³
137 of 360 measured days were over the WHO 24-hour guideline (15 µg/m³). One row per month, one square per local day.
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales

Hour by hour

No hourly readings in the last few days. The chart returns when the monitors' data arrives.

Where it stood each day

Top 10Top 100#1#10#100#1,000#2,835NovDecJanFebMarAprMayJunJulAugSep#368
Its rank on each day's world board, #1 being the most polluted city that day. The scale is logarithmic: each step down is ten times as many cities. See it among every city.

2026 against 2025, month by month

15Jan 2025: 28.5 µg/m³Jan 2026: 18.8 µg/m³JanFeb 2025: 19.7 µg/m³Feb 2026: 27.3 µg/m³FebMar 2025: 20.4 µg/m³Mar 2026: 23.5 µg/m³MarApr 2025: 15.8 µg/m³Apr 2026: 12.2 µg/m³AprMay 2025: 14.8 µg/m³May 2026: 80.9 µg/m³MayJun 2025: 14.5 µg/m³Jun 2026: 95.0 µg/m³JunJul 2025: 10.2 µg/m³Jul 2026: 64.7 µg/m³JulAug 2025: 10.6 µg/m³Aug 2026: 69.0 µg/m³AugSep 2025: 4.3 µg/m³Sep 2026: 36.3 µg/m³SepOct 2025: 5.2 µg/m³OctNov 2025: 100.6 µg/m³NovDec 2025: 45.3 µg/m³Dec
Faded bars: 2025. A month shows once it has 10 measured days.

This week against past years

This weekThis week: 8.3 µg/m³8.320252025: 4.9 µg/m³4.9
Mean PM2.5 for 25 Sept to 1 Oct in each year. Dashed line: WHO 24-hour guideline.

Monitors

StationOperatorType
홍천읍Permission requested (AirKorea, 2026-10-01)Korea Air Ministry of EnvironmentReference

The city's value is the median of its reference monitors each hour, when at least a third of them report (three are always enough); low-cost sensors are listed but not counted when reference monitors exist. Data via OpenAQ; licences as listed. How we rank. Embed this on your site.

Use this page

SmogRank, PM2.5 daily means, Hongch’ŏn, South Korea, 2 Oct 2025 – 1 Oct 2026, smogrank.com/kr/hongch-on (accessed 2 Oct 2026).

Download chart (PNG)Embed a live widget

You're welcome to reuse a single chart, image or figure with this citation and a link. Terms.

Other cities in South Korea

30-day averages, US AQI. All of South Korea.

Updated 2026-10-02 09:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index.